There are methods known in the related art through which an original map is simplified based upon map data used for map display. For instance, the apparatus disclosed in a patent reference literature 1 simplifies the original map by executing processing such as linearization or orthogonalization to linearize or orthogonalize the shapes of roads in the map data and displaying landmark information over a specific range defined with a mask. Through the display of the map having been simplified as described above, an easy-to-read map is provided.
Patent reference literature 1: Japanese Laid Open Patent